Die for making screw-threads on tubes.



No. 687,464. I Patented Nov. 26, I901.

W.-E. SULLIVAN.

DIE FUR MAKING SCREW THREADS 0N TUBES;

' (Application med'Au 5, 1901.

(No Model.)

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UNITED STATES PATENT OFFICE.

WILLIAM E. SULLIVAN, OF PROVIDENCE, RHODE ISLAND.

DIE FOR MAKING SCREW-THREADS ON TUBES.

SPECIFICATION forming part of Letters Patent No. 687,464, dated November 26, 1901.

Application filed August 5, 1901. serial 1 3 (N0 To aZZ whom it may concern.-

Be it known that I, WILLIAM E. SULLIVAN, of the city of Providence, in the county'of Providence and State of Rhode Island, have invented certain new and useful Improvements in Dies for Making Screw-Threads on Tubes; and I do hereby declare that the following is a full, clear, and exact description thereof, reference being bad to the accompanying drawings, and to the letters of reference marked thereon, which form a part of this specification.

This invention relates to that class of metalworking tools used for making screw-threads on tubes; and its object is to make the screwwork of that description faster, and on thin metal a deeper and more serviceable thread can be made than when the thread is formed by cutting away parts of the metal, as is usually done. It is fully explained and illustrated in this specification and the annexed drawings.

Figure 1 shows a side elevation of the dies for forming the screw-thread on the tubes. Fig. 2 is a side elevation showing the upper die raised. Fig. 3 is bottom view of the upper die. Fig. at is a top view of the lower die. Fig. 5 shows a vertical section of the dies, taken on line 5 5 in Fig. at, with the upper die raised and a tube with the core in it in place in the lower die.

The construction and operation of the screw-thread-forming devices are as follows:

A and A are the upper and lower members of a pair of dies, the upper one of the pair being provided with a teat B, fitted to enter the mandrel of a press and be held by a setscrew. The lower part A of the pair is made fast to taper block 0, beveled on two sides, so as to be held in the ordinary die-dish of a press. The dies are not divided horizontally directly through the middle; but a portion a of the lower die projects up into a recess cut up into the upper die, and a hole 0 is made through the two parts at the junction, so that a half of the hole is made in each die, and a screw-thread D (see Figs. 3 and 4) is cut in the hole when both parts of the die are together, as in Fig. 1. Dowel-pins gg are putin the lower part, that enter into holes in the upper part A to guide them and make sure of their coming together properly. The other member of the combination is the core H. (Seen in Fig. 5.) It consists of a steel rod with a screw-thread 8 cut on a part of it to form a screw alittle smaller than the threaded aperture in the die when the two parts are closed together, but having the same number of threads.

To use the device, the core H is put in the end of the tube J and placed between the dies, (see Fig. 5,) the upper part A being raised high enough to admit of the tube and core being put in the lower part of the die. The

.upper part A is then brought down on the tube by means of the press, and the screwthread will force the tube into the screwthread on the core and make a screw-thread on the tube J. The upper die is then raised a little Way and the tube and core turned part way around, so as to bring the sides of the tube on the top and bottom, when the die is again closed down on it and a perfect screwthread made clear around the tube. These motions may be repeated on successive portions of the tube until the desired length of screw-thread is made. Then the upper part of the die A is raised, the tube taken out, and the core H unscrewed out of it. These motions can be made very fast, and, as before stated, a deep serviceable thread can be made on a thin tube that could not be cut on it, thereby enabling the manufacturer to use lighter tubes and save cost both on the stock and labor.

I claim as my invention and desire to secure by Letters Patent- I 1. In a tube-threading apparatus the combination of a die divided into an upper and lower part, the upper part being fitted to be held in the mandrel of a press and the lower part fitted to be held in the die-dish of a press, a groove semicircular in cross-section made in the face of each part, a screw-thread made in each groove, a core consisting of a rod hav- 9 ing a screw-thread on it agreeing with the thread in the grooves, substantially as described.

2. In a tube-threading apparatus the combination of a die divided into an upper and lower part, the upper part being fitted to be held in the mandrel of apress and the lower part extended up into a recess in the upper part and furnished with dowel-pins and fitted to be held in the die-dish of a press, a groove semicircular in cross-section made in the face of each part, a screw-thread made in each groove, a core consisting of a rod having a screw-thread on it agreeing with the thread in the grooves, substantially as described. 10

In testimony whereof I have hereunto set my hand this 2d day of August, A. D. 1901.

WILLIAM E. SULLIVAN. Witnesses:

BENJ. ARNOLD, HOWARD E. BARLOW. 

